User missing from LDAP group?

I have an employee who left our company, and then returned. The account was not removed, so the employee is using the same account they were before. We are using openfire configured to read from our active directory, and I am sharing out a group I created called IM users. Most of our employees still see our newly returned prodigal, however I do not.

I think that I might have deleted her from that group in my contact list at some point. How can I restore her?

By the way, I see the same issue in 3 different IM clients: spark, pidgin, and digsby. I can manually add her to a separate group, but I cannot add her back into the group she belongs in.